Simply put, scammers take advantage of people being helpful and careless. A USB cable isn’t just for charging it can also access your data. Even with phone security features, all it takes is one moment of trust or unlocking your phone. The safest habit is to never plug your phone into unknown cables, chargers, or power banks, and always assume public or stranger owned USBs are risky. Personally I never and will not do that as it's very risky.